Why should you care?

Storing rupee amounts in FLOAT causes rounding errors on GST totals; storing phone numbers in INT drops leading zeros.

See it live — copy this example

Run in MySQL Workbench or the mysql CLI.

CREATE TABLE IF NOT EXISTS products (
  product_id   INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
  sku          VARCHAR(40) NOT NULL,
  price_inr    DECIMAL(10,2) NOT NULL,
  attrs        JSON,
  is_active    TINYINT(1) NOT NULL DEFAULT 1
);

What happened?

• price_inr uses DECIMAL(10,2) for paise-accurate money.
• attrs is JSON for color/size without ALTER every launch.
• TINYINT(1) acts as boolean for active flag.

Practice next

1. Create products table in DataFlow.
2. Insert: INSERT INTO products (sku, price_inr, attrs) VALUES ('DF-TSHIRT', 799.00, JSON_OBJECT('size','M','color','blue'));
3. Select attrs: SELECT sku, attrs->>'$.color AS color FROM products;
4. Change attrs to store an array: JSON_ARRAY('red','blue').
5. Use CAST(price_inr AS CHAR) in SELECT and compare display.

Remember

Match types to real data shape. DECIMAL for money, JSON for semi-structured fields. Wrong types cause silent bugs or insert failures.

Flipkart-style SKU attrs

New festival badge lives in products.attrs JSON instead of ten nullable columns.

Outcome: Catalog team ships badges without weekly migrations.